Impregnation of wood, &amp;c.



U ITED STATES PATENT OFFICE.

rAx RfiPING, 0E GHARLOTTENBURG, GERMANY, ASSIGNOB rro THE'FIBM 0E nuns- BERG & 01E, GESELLSCHAFT mrr EEscHRANKrEn HAETUNG, 0F GHARLOTTENBURG, GEmrANY, A conronA'rroN 0E GERMANY.

IMPREGNATION OF WOOD, &O.

Specification of Letters Patent.

30, 1904, Serial No. 234,961. Serial No. 517,914.

To all whom it may concern:

Be it known that I, MAx RfiPrNe, a subject of the German Emperor, and resident of Charlottenburg, Prussia, Germany, haveinvented new and useful Improvements in the Impregnation of Wood and other Porous Materials, of which the following is a specification. Y

My invention relates to improvements in methods of impregnating wood and other materials, this method being an improvement on my former patent, Reissue No. 12,707, dated'O'ctober 22, 1907.

This invention relates to the so-called empty cell method of impregnation and is adapted for the impregnation of all sorts of porousmaterials, such as fabrics, wood, peat, paper, felt, artificial stone, and the like, but lts principal use is for impregnating railway ties, bridge and wharf timbers, and wooden articles which are exposed to the weather, for the purpose of preserving the same.

The methods used formerly had for their object the filling up of the cells or pores and hollow places of the material under treatment with the impregnating liquid; In contradistinction thereto, it is the object of my present invention, as well as 'of the reissue patent hereinbefore referred to, not to fill up the cells, pores, and cavities, completely with the impregnatin liquid, but only to impregnate the1r wa s with said liquid, or in other words to provide them with a coating of the latter and to leave the cells, pores, and cavities empty. The impregnating liquid which I prefer to use is creosote or heavy oil oftar, but I do not restrict myself to this particular liquid.

This method consists in subjecting the air dried wood or other material submerged in the impregnating liquid in a closed vessel to a pressure sufficient to force the desired quantity of the preservative into the material, this pressure preferably not exceeding about three atmospheres. After this treatment has been continued for a short time, an hour or two for example, the impregnating liquid is drawn ed and a vacuum established in the vessel. The air which has been compressed in the material while the preservative'is being forced into the material vacuum,

then expands and forces out a part of the liquid which has entered the pores of the Wood, and this liquid is then drained OK. This treatment under a vacuum is continued for a short time, say from halfan hour to two hours more or less, for example. Air or an inert gas is then forced into the vessel under a pressure of up to six atmospheres and even more according to the nature of the material under treatment which pressure has the effect of causing the air or other gas to enter into the cells of the wood. This gas pressure treatment is continued for a short time, a half an hour or an hour for example, and then the pressure is released and a vacuum again established in the vessel, whereupon the air which has been forced into the material under treatment expels an .additional quantity of the impregnating liquid. g

The two steps last described may be repeated indefinitely, but it is desirable that the last step should be the vacuum treatment and not the gas pressure treatment, as the former (viz. the vacuum treatment) upon Patented Nov. 14, 1911. I Renewed September 1591909.

reestablishing the atmospheric air pressure around the treated material will result in forcing the impregnating liquid into the interior of the wood or other'substance treated, leaving the outside dry.

I claim v 1. The method of impregnating wood and other poro'us materials',' which consists in subjecting the material under treatment to the action of an impregnating liquid at a pressure greater than that of the atmospheric air, and then subjecting the material to a vacuum, then breaking the vacuum, and subjecting the material to a gas pressure higherthan that of the atmospheric air, and then reestablishing the vacuum, substantially as described.

2. The method of impregnating wood and other porous materials, consisting in subjecting the material under treatment to the action of an impregnating liquid under a pressure of not more than three atmospheres, then. subjecting'the material to then subjecting the material to a gas pressure of several atmospheres and then reestablishing the vacuum, substantially as described.

5 a pressure of not more than three atmos- 3. The' method of impregnating wood said gas ressure aml -vacuum treatments, 10 andother plorous materials, consisting in substantia y as described.

Isubjecting t e material under treatment to p In testimony whereof, I aflix my slgnathe actlon of an impregnating l1 qu1d under 'ture, inpresence of two witnesses.

.- pheres, thensubjecting the material to a RUPING' vacuum, then subjecting'the material to a Witnesses: gas pressure of several atmospheres and then Wonimmn HAUPT,

restablishing the vacuum and repeating HENRY HASPER. 

